1. Field of the Invention
This invention relates generally to alarm systems and particularly to a mechanism for actively alerting an operator of the occurrence of a specific condition requiring the attention of the operator.
2. Discussion of the Related Art
Substantially all mechanical devices, and in particular vehicles, have structures which have a xe2x80x9cnatural frequency.xe2x80x9d The xe2x80x9cnatural frequencyxe2x80x9d of a component is the frequency at which a system oscillates in the absence of external forces; or, for a system with more than one degree of freedom, the frequency of one of the normal modes of vibration. Particular care is given during the designing of these components to avoid the xe2x80x9cnatural frequency.xe2x80x9d The goal in most cases is to remove unwanted vibration to provide smooth and comfortable operation of the machine.
From an automobile manufacturer""s viewpoint, the natural frequency of a component or assembly should be higher than a particular threshold, else the operator of the vehicle may detect some undesirable vibration, rattle, or xe2x80x9csingingxe2x80x9d during operation which is distracting, annoying, or disconcerting. Always, when an automobile manufacturer provides specifications to outside or third party vendors/suppliers, the natural frequency floor for the desired component/assembly is usually set out and is to be avoided. To the best of the inventor""s knowledge, never has the natural frequency of a component been used to alert the operator of a condition.
The instant invention is an apparatus for interconnecting two objects together and permits the relative position of the two objects to be adjusted while the device is in a first state, and fixes the relative position of the two objects while the device is in a second state. The state of the device can be dynamically driven, and in particular, xe2x80x9ctunedxe2x80x9d to either avoid, or induce, the natural frequency of the coupled structures.
The apparatus embodying the invention includes a housing having at least one movable piston inside. Also inside the housing is a non-Newtonian flow fluid which passes through at least one passage within the housing. Adjacent the passage, or in close proximity thereto, is a device for selectively generating or neutralizing a magnetic field in and around the passage. The fluid within the housing flows through the passage when the magnetic field is weak or absent permitting the piston to move. When the magnetic field surrounding the passage reaches a predetermined strength, the fluid undergoes a change and ceases to flow, locking the relative position of the piston within the housing. If the strength of the field is increased, the effect of the field extends beyond that of the passage, and renders the device to be more rigid.
In one form of the invention, the invention is used to adjustably fix the relative position of the two interconnected components. The novel assembly includes an upper housing assembly coupled to a lower housing assembly in a manner to permit at least one of the upper and lower housing assemblies to articulate and telescope relative to the lower housing assembly. At least one non-Newtonian flow fluid-locking mechanism interconnects the upper housing assembly to the lower housing assembly for selectively fixing their relative positions. It is contemplated the apparatus includes a device for generating a magnetic field around at least a portion of the non-Newtonian flow fluid-locking mechanism for selectively activating and deactivating the fluid-locking mechanism. An electronic circuit and sensors are interconnected to the non-Newtonian flow fluid-locking device to dynamically adjust the strength of the magnetic field, thereby adjusting the rigidity of the locking mechanism. In the event the sensors detect the occurrence of a predetermined event, the strength of the magnetic field in the locking mechanism is changed to match the natural frequency of the component which produces one of an audible, tactile or visible signal to the operator. For example, in the event a sensor detects an object adjacent the left side of the vehicle, the circuit may be programmed to increase the magnetic field in the locking mechanism which controls the turn rate of the steering wheel, essentially providing tactile feed back to the operator which makes it more difficult to turn left and into the obstacle.
In yet another form of the invention, it is contemplated that the invention may be used to lock the rotation of the steering column, and act as a vehicle anti-theft system in the event the vehicle is broken into. The system would not deactivate until the key was inserted or some other system releases the device. Additionally, it is contemplated that the invention may be used to fix the relative position of seats, control pedals, and other objects within a vehicle, or match the natural frequency of those components such that they vibrate and provide a physical stimulus to the operator.
In still another form of the invention, an adjustable steering column is provided which is capable of tilting, telescoping, or both to the operators desired position. The locking system provided to fix the desired position of the steering column is dynamically adjusted or xe2x80x9ctunablexe2x80x9d in and out of the natural frequency of the steering column so the steering column vibrates upon the occurrence of a predetermined event. Sensors are mounted on the steering column to provide feedback via a logic system or computer to alter the stiffness of the locking system and increase or decrease the vibration of the column. For example, sensors could monitor the operator""s eyes and determine when he/she has fallen asleep. If a condition is met, the locking mechanism is adjusted to permit the column to vibrate, and wake-up the operator. Once the condition is no longer satisfied, the system is tuned so the vibration stops and returns to normal operation. Similar systems could be used with seats, shift levers, control pedals, and the like.
These and other objects, advantages, purposes, and features of the invention will become more apparent from a study of the following description taken in conjunction with the drawing figures described below.